Etude de la toxicité du filtrat de culture de Botrytis cinerea sur des vitroplants de vignes: I. Effet du filtrat brut

Study of culture filtrate toxicity of Botrytis cinerea observed on grapevine vitroplants:I. Effect of crude culture filtrateThe purpose of this research was: to show culture filtrate toxicity of Botrytis cinerea,to determine an eventual relation between susceptibility of grapevines to B. cinerea in the field and susceptibility of in vitro plantlets to fungal culture filtrate.In this way, effects of culture filtrate on the growth of vitroplants were examined to evaluate on the one hand, susceptibility of Vitis and, on the other, degree of culture filtrate toxicity. Growth inhibition increased with grapevine sensitivity and no phytotoxic effects were observed on resistant grapevines. So a discrimination between resistant, susceptible and very susceptible grapevines was achieved. A comparative study has also shown that factors like fungal culture age or isolate nature were able to affect toxicity. 1-week-old culture filtrate was able to induce symptoms on vitroplants and toxicity increased with fungal culture age. Moreover, this was not due to enzyme activity

Etude de la toxicité du filtrat de culture de Botrytis cinerea sur des'vitroplants de vignes: II. Effet des différentes fractions isolées a partir du filtrat brut

Study of culture filtrate toxicity of Botrytis cinerea observed on grapevine vitroplants:II. Effect of various fractions isolated from the crude culture filtratePolysaccharides secreted by Botrytis cinerea were isolated from the crude culture filtrate and precipitated as two fractions: glucan and heteropolysaccharides. The fraction containing heteropolysaccharides was further separated into two sub-fractions. The phytotoxic activities of the various fractions were tested on vitroplants from several grapevines differing in their sensitivity to B. cinerea. With glucan, no toxic effects on the growth of vitroplants were observed. The heteropolysaccharides showed specific phytotoxic activities which were identical with the effects of the culture filtrate: plants susceptible to the pathogen were also susceptible to the heteropolysaccharides, and vice versa

High rate, long-distance quantum key distribution over 250km of ultra low loss fibres

We present a fully automated quantum key distribution prototype running at 625 MHz clock rate. Taking advantage of ultra low loss fibres and low-noise superconducting detectors, we can distribute 6,000 secret bits per second over 100 km and 15 bits per second over 250km

The SECOQC quantum key distribution network in Vienna

In this paper, we present the quantum key distribution (QKD) network designed and implemented by the European project SEcure COmmunication based on Quantum Cryptography (SECOQC) (2004–2008), unifying the efforts of 41 research and industrial organizations. The paper summarizes the SECOQC approach to QKD networks with a focus on the trusted repeater paradigm. It discusses the architecture and functionality of the SECOQC trusted repeater prototype, which has been put into operation in Vienna in 2008 and publicly demonstrated in the framework of a SECOQC QKD conference held from October 8 to 10, 2008. The demonstration involved one-time pad encrypted telephone communication, a secure (AES encryption protected) video-conference with all deployed nodes and a number of rerouting experiments, highlighting basic mechanisms of the SECOQC network functionality.The paper gives an overview of the eight point-to-point network links in the prototype and their underlying technology: three plug and play systems by id Quantique, a one way weak pulse system from Toshiba Research in the UK, a coherent one-way system by GAP Optique with the participation of id Quantique and the AIT Austrian Institute of Technology (formerly ARCAustrian Research Centers GmbH—ARC is now operating under the new name AIT Austrian Institute of Technology GmbH following a restructuring initiative.), an entangled photons system by the University of Vienna and the AIT, a continuous-variables system by Centre National de la Recherche Scientifique (CNRS) and THALES Research and Technology with the participation of Université Libre de Bruxelles, and a free space link by the Ludwig Maximillians University in Munich connecting two nodes situated in adjacent buildings (line of sight 80 m). The average link length is between 20 and 30 km, the longest link being 83 km.The paper presents the architecture and functionality of the principal networking agent—the SECOQC node module, which enables the authentic classical communication required for key distillation, manages the generated key material, determines a communication path between any destinations in the network, and realizes end-to-end secure transport of key material between these destinations.The paper also illustrates the operation of the network in a number of typical exploitation regimes and gives an initial estimate of the network transmission capacity, defined as the maximum amount of key that can be exchanged, or alternatively the amount of information that can be transmitted with information theoretic security, between two arbitrary nodes

A fast and versatile quantum key distribution system with hardware key distillation and wavelength multiplexing

We present a compactly integrated, 625 MHz clocked coherent one-way quantum key distribution system which continuously distributes secret keys over an optical fibre link. To support high secret key rates, we implemented a fast hardware key distillation engine which allows for key distillation rates up to 4 Mbps in real time. The system employs wavelength multiplexing in order to run over only a single optical fibre. Using fast gated InGaAs single photon detectors, we reliably distribute secret keys with a rate above 21 kbps over 25 km of optical fibre. We optimized the system considering a security analysis that respects finite-key-size effects, authentication costs and system errors for a security parameter of εQKD = 4 × 10−9

The SECOQC quantum key distribution network in Vienna

International audienceThe paper presents the architecture and functionality of the principal networking agent—the SECOQC node module, which enables the authentic classical communication required for key distillation, manages the generated key material, determines a communication path between any destinations in the network, and realizes end-to-end secure transport of key material between these destinations. The paper also illustrates the operation of the network in a number of typical exploitation regimes and gives an initial estimate of the network transmission capacity, defined as the maximum amount of key that can be exchanged, or alternatively the amount of information that can be transmitted with information theoretic security, between two arbitrary nodes